The oxidative conversion of olefinic hydrocarbons to carbonylic compounds



United States Patent 3,293,291 THE OXIDATIVE CONVERSION OF OLEFINIC HY- DROCARBONS T0 CARBONYLIC COMPOUNDS Freddy Wattimena, Amsterdam, Netherlands, assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Apr. 5, 1963, Ser. No. 270,825 Claims priority, application Netherlands, May 29, 1962,

79,024 6 Claims. (Cl. 260-533) as in aldehydes, ketones and carboxylic acids.

A potential source of carbonylic compounds comprises the readily available olefinic hydrocarbons. Processes disclosed heretofore directed to the oxidative conversion of olefins comprise those, the efiicient utilization of which is limited with respect to the olefinic charge to which they can be applied. Of those available heretofore, those intended to be applied to more diversified olefinic charge materials often result in relatively high conversions to undesired by-products or necessitate the use of systems which are either difficult to maintain at optimum conditions or which are relatively costly to install .a-nd operate. Among the latter type may often be included those comprising the use of liquid phase catalyst systems.

It is therefore an object of. the present invention to provide an improved process enabling the more efficient oxidative conversion of olefinic hydrocarbons to carbonylic compounds with the aid of a solid combination catalyst.

Another object of the invention is the provision of an improved process enabling the more efficient oxidative conversion of normally gaseous olefinic hydrocarbons to corresponding carbonylic compounds with the aid of an improved, solid combination catalyst.

A specific object of the invention is the provision of an improved process enabling the more efficient oxidative conversion of olefinic hydrocarbons comprising ethylene to reaction mixtures comprising substantial amounts of acetaldehyde and/or acetic acid with the aid of an improved, solid combination catalyst. Other objects and advantages of the present invention will become apparent from the following detailed description thereof.

In accordance with the invention, olefinic hydrocarbons are oxidat-ively converted to corresponding carbonylic compounds by reaction with oxygen in vapor phase, at a temperature below about 350 C., in the presence of water vapor, a halogen, and of a solid four component combination catalyst comprising (a) a noble metal of Group VIII of the periodic system in combination with (b) a transition element from Groups "I, VII and VIII other than said noble metal, (c) an alkali metal of atomic numbers 11 through 55, and (d) a transition element taken from Groups III through VI including the rare earth elements of atomic numbers 57 through 71.

THE CATALYST Essential to the attainment of the objects of the invention is the presence of a catalyst comprising in combination at least one member of. each of the following components A, B, C and D:

"ice

Component A comprises at least one member of the noble metals of Group VIII of the Periodic Table of the elements. These comprise ruthenium, rhodium, palladium, osmium, iridium and platinum. Of these, palladium is preferred.

Component B comprises a member of the transition elements of Groups I, VII and VIII of the Periodic Table of the elements excluding the noble metals of Group VIII. Particularly suitable components include copper, silver, iron, cobalt and nickel. are preferred. Particularly preferred is copper.

Component C comprises an alkali metal having an atomic number of from 11 to 55 inclusive; potassium being [generally preferred. The presence of the alkali metal component increases substantially the activity of the solid combination catalyst, increasing materially the yield of desired :carbonylic product.

Component D comprises at least one member of the transition elements of Groups III through VI of the Periodic Table of the elements including the rare earth elements having an atomic number of 57 through 71. Particularly suitable are zirconium, titanium, vanadium, chromium, molybdenum, hafnium, tungsten and the rare earth elements. The presence of the component D, it has been found, has a decided advantageous effect, not only upon the activity of the catalyst but pon its stability over prolonged periods of time and selectivity toward the carbonylic products. The rare earth elements, especially the mixtures thereof. known as didymium, are particularly effective. .Didymium, the preferred component D, generally comprises an admixture of lanthanum and neodymium as well as lesser amounts of praseodymium and samarium. The specific proportion of each component of didymium is not critical and may vary widely within the scope of the invention. Thus a suitable specific didymium component B is found to have the following composition: La -O 45%, ND 'O 38%, Pr O 11%, Sm O 4%, miscellaneous rare earths 2%.

The components of the combination catalyst are present in the form of suitable compounds thereof, for example, as the salts of inorganic acids, particularly as halides, preferably chlorides and sulfates. Each component may initially be present in the form of substantially the same salt or a plurality of salts. Thus a component may initially be present as the chloride, the sulfate and/or mixtures thereof. A part of each component may furthermore initially be present in other forms, as for example, the elementary state, as an oxide, a metallate, a heteropoly acid, and the like. i

In general, the individual components of the catalyst are present as cations. However, their presence in the form of an anionic portion of the constituent molecule is comprised Within the scope of the invention, for example, as in heteropoly acids such as molybdates, silicom-olybdates, soilocot-ungstates, etc.

The combination catalysts may be employed as such or in combination with a suitable support material. Any conventional catalyst support material may be employed within the scope of the invention. These are, however, not all equivalent in suitability. Suitable supports comprise, for example, pumice, alumina, silica-alumina, clays, etc. By far the best results are obaine-d with catalysts comprising silica gel as carrier. Particularly effective are the silica gel supports having a surface area of at least 1 m. g. and an average pore diameter of at least A.

The relative proportion of each of the four catalyst components A, B, C and D defined above, in the combination catalyst may vary Within the scope of the inven- Of these, copper and/ or cobalt tion. Best results are, however, obtained with the combination catalysts of the above-defined class wherein are present from about 3 to about 15 atoms of each of the components B and C, and from about one to about seven atoms of component D, for each atom of component A.

Of the four-component combination catalyst defined herein, those comprising a part of the components in the form of chlorides and another part in the form of sulfates are preferred. The presence of the sulfate ion has been found to influence favorably to an important degree the selectivity to carbonylic compounds while suppressing undesired CO and CO producing reactions. The ratio of halides to sulfates in the catalysts is preferably maintained above about 0.4, for example, up to about 0.8. In general, those catalysts are preferred wherein at least about 30%, up to, for example, about 80%, of the anions of the metal components therein are sulfate ions. Anions other than sulfate and/ or halide ions which may be comprised in the combination catalysts of the invention include, for example, selenates, phosphates, mixtures thereof, etc.

The members of the above-defined four-component catalysts are not necessarily equivalent. Outstanding in their ability to effect efficiently the oxidative conversion of olefins are those combining potassium as component C, with the rare earth elements as component D. Of these preferred combination catalysts, those comprising didymium as component D are particularly preferred. Specific examples of the latter are the combinations consisting essentially of admixtures of chlorides and sulfates of: palladium-copper-potassium-didymium, and palladium-cobalt-potassium-didymium, on silica support. A particularly preferred catalyst comprises, for example, the combination PdCl CuSO K SO -DiCl on silica.

The components of the catalyst combinations may be combined in any of many ways. Thus the components may be admixed in dry state, or a part or all may be combined as pastes or solutions and the mixtures dried. The catalyst support may be added during and/or after combining the components. The elementary catalyst components may be converted to the desired form (chlorides and/or sulfates, etc.) after or before combining by conventional means.

The catalyst support may be calcined separately before combining with the catalyst components. The supported catalyst itself may be subjected to pretreatment at elevated temperatures, for example, from about 100 to about 350 C. in the presence of oxygen-containing gas and/or halogen, hydrogen halide (HCl) or the like.

REACTANTS Oxidatively converted in the process of the invention are the olefinic hydrocarbons, broadly. Specific examples are: the mono-olefins such as ethylene, propylene, the butenes and amylenes; the primary, secondary, branched and cyclic olefins, as pentene-l, butene-Z, hexene-l, hexene-2, the amylenes, heptenes, octenes; cyclobutene, cyclopentene, etc.; olefinic fractions obtained in thermal or catalytic petroleum refinery operations; cracked wax olefins; olefinic hydrocarbon products emanating from halogenation, dehalogenation, hydrohalogenation or dehydrohalogenation processes, etc.; diolefins such as butadiene, pentadiene-1,4, isoprene; aromatic olefins, as styrene. The suitable olefinic charge may contains saturated hydrocarbons admixed therewith. Such saturated hydrocarbons may be added willfully to the charge to aid in maintaining desired operating conditions.

The oxygen charge may consist of oxygen, diluted oxygen, oxygen-containing gas, such as air or the like. Inert gas, such as nitrogen, may be used as diluent.

The oxygen and/or olefin charge may be introduced separately or as combined streams into the reaction zone at one or more points along the length thereof. The charge may be subjected to suitable pretreatment to effeet the removal of undesired components therefrom. Such pretreatment may comprise one or more such steps as absorption, adsorption, distillation, chemical treatment or the like.

REACTION CONDITIONS The olefinic charge is reacted with oxygen in the presence of the above-defined catalysts at a temperature below about 350 C. Temperatures from about 180 to about 350 C. are generally preferred. Temperatures outside of this range, for example as low as 50 C., may, however, be employed Within the scope of the invention. The specific temperature preferably employed will depend to some extent upon the specific olefinic charge and catalyst present.

The ratio of olefin to oxygen may vary within the scope of the invention. In general, a volumetric ratio of olefin to oxygen in the range of from about 0.5:1 to about 10:1 is satisfactory. Higher or lower ratios may, however, be used.

The reaction may be executed at atmospheric or superatmospheric pressures. Space velocities ranging, for example, from about 10 to about 1000, and preferably from about 20 to about 200 liters of olefinic feed per liter of catalyst per hour are suitable.

The reaction is preferably carried out in the presence of water vapor. The proportion of water vapor to reactants may vary widely within the scope of the invention. Thus, a mol ratio of water vapor to olefin of from about 0.25 to about 25 and higher may suitably be used.

The reaction is executed in the presence of added halogen. The halogen may be present as a free halogen or as hydrogen halide and may be generated in situ by addition of organic or inorganic halides liberating the halogen in the required amount. Preferred halogen is chlorine which may also be present in part as such or as HCl. The presence of the halogen and/or hydrogen halide is assured by addition to the charge or by separate introduction, continuously or intermittently, during the course of the operation. The halogen may be introduced as an organic compound, halogenated hydrocarbon, for example, such as an alkyl chloride, e.g., methyl chloride, ethyl chloride, ethylene dichloride; vinyl chloride; as inorganic metal chloride dust, vapor or the like.

Although the presence of free halogen and/ or hydrogen halide is essential to efiicient operation of the process, the relative proportion thereof is critical. It must be present in only relatively small proportions, for example, in the range of from about 0.001 to about 0.5 atom of halogen (or mol of hydrogen halide) per mol of olefin. Chlorine and/ or hydrogen chloride are preferred.

The process of the invention may be carried out with the use of the solid four-component combination catalyst in the form of a fixed bed or in a fluidized system. The catalyst also lends itself to eflicient utilization in the form of a suspension in the gaseous reaction mixture, for example, in riser-type reactors. Depending upon the specific suitable catalyst combinations and reaction conditions employed portions, at least, of the catalyst upon the surface of the catalyst support may at times be in molten state during the course of the process.

Under the abovedefined conditions, the olefinic charge is converted to reaction products comprising carbonylic compounds generally having the same number of carbon atoms as the olefinic charge. The specific carbonylic compounds obtained will depend upon the specific olefin charged and to some extent the reaction conditions used. When ethylene is charged, the principal reaction products will consist of acetaldehyde and acetic acid. The relative proportion of these products obtained may be controlled. Thus it is found that within the above-defined range of operating conditions, acetic acid production increases directly with increase in temperature and/or with increase of contact time. When propylene is charged, dimethyl ketone is generally the predominant reaction product; propionaldehyde, acetic acid and some propionic acid also being obtained. When charging butene-l and/or butene-2, the principal product is generally methyl ethyl ketone in addition to some butyraldehyde, and butyric acid-containing carbonylic products. Similarly, other olefins are converted to carbonylic products containing aldehydes, ketoncs and carboxylic acids corresponding to the olefinic charge.

The resulting reaction mixture is subjected to suitable product recovering means which may comprise one or more such steps as distillation, solvent extraction, absorption, adsorption, and the like. Unconverted reactants are recycled to the reaction zone. Reaction products, for example, of aldehydic character, may be recycled to increase the yield of carboxylic acidand ketone-containing reaction products.

EXAMPLES The catalysts used in the following examples were prepared by impregnating silica gel, which had been heated for 2 hours at 500 C., with aqueous solutions of the catalyst components in controlled amounts. The impregnated silica gel was dried, with stirring, and thereafter heated at 300 C. in an oven for three hours.

In the examples below the composition of the catalysts is expressed in millimoles per liter of silica gel carrier.

EFFECT OF CATALYST COMPOSITION (EXAMPLES I-III) Example I A gaseous mixture consisting of ethylene, oxygen, nitrogen, hydrochloric acid gas and water vapor in a molar ratio of 1:1:6:0.08:6, respectively, was passed through a fluidized catalyst at 236 C. The catalyst had the following composition:

50 PdCl 346 CuSO 173 K 80 The space velocity calculated in liters of ethylene (NTP) per liter of catalyst per hour was 87.6. The linear gas 1 rate was 5.1 cm./ second.

Analysis of the reaction mixture showed that 29.3% m. of the ethylene had been converted. The selectivity toward acetaldehyde was 37.2% and that toward acetic acid, 46.4%. Of the ethylene converted, 6.1% was oxidized to CO Example II An experiment was carried out under substantially the same conditions as in Example I, with the exception that the catalyst contained, in addition to the components there mentioned, also an amount of DiCl equal to 154. The linear gas rate was 11 cm./ second.

The ethylene conversion now amounted to 67.9% m. The selectivity toward acetaldehyde was 63.6%, that toward acetic acid 184%. Of the ethylene converted, 13.4% was oxidized to CO Example 111 For purposes of comparison, an experiment was carried out with a catalyst containing no alkali compound at a temperature of 228 C., other reaction conditions being the same as in Examples I and II. The catalyst had the following composition:

PdCl 346 CuSO l54 DiCl The linear gas rate was 5 cm./ second.

The ethylene conversion was only 11.2% m.; no more than traces of acetaldehyde were detected in the reaction mixture.

EFFECT OF THE CONTENT OF sULFATE IONS (EXAMPLES IVVI) Example IV A gaseous mixture consisting of ethylene, oxygen, nitrogen, hydrochloric acid gas and water in a molar ratio of 1: /2 :2:0.2:4, respectively, was passed through a fluidized catalyst at 292 C. The space velocity was 160 liters of 6 ethylene (NTP) per liter of catalyst per hour; the linear gas rate, 5.1 cm./second.

The catalyst employed had the following composition:

50 PdCl -346 CuCl 173 K SO l54 DiCl so that the ratio of sulfate ions to chlorine ions was 0.14. At the end of the experiment, it was found that 24.3%

m. ethylene had been converted, 7.0% of which to acetaldehyde, 11.1% to acetic acid, and 34.6% to CO Example V An experiment was carried out under substantially the same conditions as employed in Examples IV, but with the exception that a catalyst with a higher content of sulfate ions was used. This catalyst hadthe following composition:

50 PdCl 346 CuSO 346 KCl154 DiCl so that the ratio of sulfate ions to chlorine ions was 0.38. An ethylene conversion of 36% m. was attained. Of

the ethylene having reacted, 24.4% was converted to acetaldehyde, 38.1% to acetic acid, and 13.6% to CO Example VI The operation of Examples IV and V was repeated under conditions which were the same except for the presence of a still higher content of sulfate ions. This catalyst had the following compositions:

5O PdCl 346 CuSO -173 K SO 154 DiCl so that the ratio of sulfate ions to chlorine ions was 0.92.

An ethylene conversion of 36.2% m. was attained, the selectivities to acetaldehyde, acetic acid and CO being 31.5%, 40.3% and 13.3%, respectively.

EFFECT OF OXYGEN CONCENTRATION ON CONVERSION (EXAMPLES VII AND VIII) Example VII A gas mixture was passed through a fluidized catalyst at 278 C. with a linear velocity of 5 cm./second and a space velocity of 160 liters ethylene per liter of catalyst per hour. The gas mixture consisted of ethylene, oxygen, nitrogen, hydrochloric acid gas and water vapor in a molar ratio of 1:0.25:2.3:0.1:4, respectively.

The catalyst had the following composition:

PdSO 346 CuSO l73 K SO 154 DiCl Of the ethylene intake 20.5% m. proved to have been converted, 39.5% of which to acetaldehyde, 30.7% to acetic acid, and 8.8% to CO Example VIII EFFECT OF MOLAR RATIO HYDROCHLORIC ACID oAs:oLEF1N (EXAMPLEs IX-XII) Example IX A feed consisting of ethylene, oxygen, nitrogen, hydrochloric acid gas and water vapor in a molar ratio of 1: /2 :2:0.2:4, respectively, was passed through a fluidized catalyst at 220 C. The space velocity amounted to liters of ethylene per liter of catalyst per hour, the linear gas rate being cm./ second. The catalyst composition was as follows:

An ethylene conversion of 27.8% In. was attained. The selectivities toward acetaldehyde, acetic acid and CO were 38.5%, 12.6% and 5.0%, respectively.

Example X For comparison, the same catalyst was used in an experiment at a reaction temperature of 228 C. and a molar ratio of hydrochloric acid gas to ethylene of 0.1, all other conditions being the same as those mentioned in Example IX.

29.1% m. ethylene proved to have been converted, 51.5% of which to acetaldehyde, 20.6% to acetic acid, and 5.5% to CO Example XI An experiment was performed with the same catalyst, in which the molar ratio of hydrochloric acid gas to ethylene had been reduced to 0.05. The reaction temperature was 226 C., all other conditions being the same as in Example IX.

Ethylene conversion proved to be 28.9% m., 66.1% of which to acetaldehyde, 17.3% to acetic acid, and 6.2% to CO2.

Example XII In a series of experiments, gaseous feed consisting of ethylene, air, water vapor and hydrogen chloride was passed through a fluidized bed of catalyst of the following composition:

90 PdCl -346 0150 -173 K,so.,-154 DiCl,

with an initial reaction temperature of 210 C. and a space velocity of 1225 liters per liter of catalyst per hour. The molar ratio of C H :air:water vapor in the feed was 112.5:4, respectively. The molar ratio of I-ICl to C H in the feed is given for each run in the following Table A. The results in terms of conversion of C H percent selectivity to acetaldehyde and to acetic acid are given in Table A.

Example XIII A gaseous feed consisting of ethylene, oxygen, nitrogen, water vapor, hydrogen chloride in a mol ratio 1:1:6:6:0.08, respectively, was passed through a fluid bed of catalyst of the composition 75 PdCl 5l9 CuSO -259.5 K SO.;231 DiCl at a temperature of 230-250 C. and a space velocity of 1230 liters per liter of catalyst per hour. There was obtained a conversion of ethylene of 73% with a selectivity to acetaldehyde of 60%, to acetic acid of 25%, and to CO of 12%.

Example XIV The experiment of Example XIII was repeated under substantially identical conditions but with the exception that propylene was substituted for ethylene in the charge. A propylene conversion of 38% was obtained with a se- Example XV The experiment of Examples XIII and XIV were repeated under substantially identical conditions but with the exception that a feed consisting of butene1, oxygen, nitrogen, water vapor and hydrogen chloride, in a molar ratio of 1:0.75:3.3:3.6:0.05 was used. A butene conversion or 14% was obtained with a selectivity to methyl ethyl ketone of 39%.

The experiment was repeated substituting butene-2 for butene-1 in the charge. A conversion of butene of 10% with a selectivity to methyl ethyl ketone of 32% was obtained.

I claim as my invention:

1. The process for the oxidative conversion of a monoolefinic hydrocarbon having from two to about ten carbon atoms to the molecule to carbonylic compounds selected from the group consisting essentially of aldehydes, ketones and monocarboxylic acids, which consists essentially of contacting said monoolefin in admixture with oxygen, water vapor, and from about 0.001 to about 0.5 atom molecule of hydrogen chloride for each molecule of olefin present, in vapor phase, at a temperature of from about 180 to about 350 C. with a solid combination cat-alyst consisting essentially of (A) about one atom divalent palladium in combination with (B) from about 3 to about 15 atoms of divalent copper, (C) about one to about 7 atoms of an alkali metal having an atomic number of 11 through 55 and (D) from about 3 to about 15 atoms of trivalent didymium, said palladium, copper, alkali metal and didymium being present in the form of chlorides and sulfates.

2. The process in accordance with claim 1 wherein said alkali metal is potassium.

3. The process in accordance with claim 2 wherein from about 30 to about of the anion content of said solid combination catalyst are sulfate ions.

4. The process for the oxidative conversion of ethylene to carbonylic products consisting essentially of acetaldehyde and acetic acid, which consists essentially of contacting said ethylene in admixture with oxygen, water vapor, and from about 0.001 to about 0.5 molecule of hydrogen chloride per molecule of said ethylene, in vapor phase, at a temperature of from about to about 350 C. with a solid combination catalyst consisting essentially of (A) about one atom of divalent palladium in combination with (B) from about 3 to about 15 atoms of divalent copper, (C) from about one to about 7 atoms of trivalent didymium, and (D) from about 3 to about 15 atoms of potassium, said palladium, copper, didymium and potassium being present in the form of chlorides and sulfates, and said solid combination catalyst contains a ratio of sulfate to chloride ions of from about 0.4 to about 0.8.

5. The process for the oxidative conversion of propylene to carbonylic product consisting essentially of dimethyl ketone and propionaldehyde, which consists essentially of contacting said propylene in admixture with oxygen, water vapor, and from about 0.001 to about 0.5 molecule of hydrogen chloride per molecule of said propylene, in vapor phase, at a temperature of from about 180 to about 350 C. with a solid combination catalyst consisting essentially of (A) about one atom of divalent palladium in combination with (B) from about 3 to about 15 atoms of divalent copper, (C) from about one to about 7 atoms of trivalent didymium, and D) from about 3 to about 15 atoms of potassium, said palladium, copper, didymium and potassium being present in the form of chlorides and sulfates, and said solid combination catalyst contains a ratio of sulfate to chloride ions of from about 0.4 to about 0.8.

6. The process for the oxidative conversion of butenes to carbonylic products comprising ethyl methyl ketone which consists essentially of contacting said butenes in admixture With oxygen, water vapor, and from about 0.001 to about 0.5 molecule of hydrogen chloride per molecule of said bu-tenes, in vapor phase, at a temperature of from about 180 to about 350 C. with a solid combination catalyst consisting essentially of (A) about one atom divalent palladium in combination With (B) from about 3 to about 15 atoms of divalent copper, (C) from about one to about 7 atoms of trivalent didymium, and (D) from about 3 to about 15 atoms of potassium, said palladium, copper, didymium and potassium being present in the form of chlorides and sulfates, and said solid combination catalyst contains a ratio of sulfate to chloride ions of from about 0.4 to about 0.8.

References Cited by the Examiner UNITED STATES PATENTS 1,871,117 8/1932 Day 252462 2,690,457 9/ 1954 Hackman 260-58'6 3,057,915 10/ 1962 Riemenschneider et :al.

LORRAINE A. WEINBERGER, Primary Examiner.

LEON ZITVER, Examiner.

I. R. PELLMAN, S. B. WILLIAMS,

Assistant Examiners. 

1. THE PROCESS FOR THE OXIDATIVE CONVERSION OF A MONOOLEFINIC HYDROCARBON HAVING FROM TWO TO ABOUT TEN CARBON ATOMS TO THE MOLECULE TO CARBONYLIC COMPOUNDS SELECTED FROM THE GROUP CONSISTING ESSENTIALLY OF ALDEHYDES, KETONES AND MONOCARBOXYLIC ACIDS, WHICH CONSISTS ESSENTIALLY OF CONTACTING SAID MONOOLEFIN IN ADMIXTURE WITH OXYGEN, WATER VAPOR, AND FROM ABOUT 0.001 TO ABOUT 0.5 ATOM MOLECULE OF HYDROGEN CHLORIDE FOR EACH MOLECULE OF OLEFIN PRESENT, IN VAPOR PHASE, AT A TEMPERATURE OF FROM ABOUT 180* TO ABOUT 350* C. WITH A SOLID COMBINATON CATALYST CONSISTING ESSENTIALLY OF (A) ABOUT ONE ATOM DIVALENT PALLADIUM IN COMBINATION WITH (B) FROM ABOUT 3 TO ABOUT 15 ATOMS OF DIVALENT COPPER, (C) ABOUT ONE TO ABOUT 7 ATOMS OF AN ALKALI METAL HAVING AN ATOMIC NUMBER OF 11 THROUGHS 55 AND (D) FROM ABOUT 3 TO ABOUT 15 ATOMS OF TRIVALENT DIDYMIUM, SAID PALLADIUM, COPPER, ALKALI METAL AND DIDYMIUM BEING PRESENT IN THE FORM OF CHLORIDES AND SULFATES. 